| Leo Music Archives | Most of the Birthdays |
| OperaGlass | All of the French Operas |
| Really Useful Theatre Company | Opening nights of Andrew Lloyd Webber's musicals |
| Number One Hits (Currently Offline) | The chart listings |
| Super BPM Charts | More chart listings |
| Musicals Database (Currently Offline) | Opening nights of other well-known musicals |
| Composer Birth/Death Database | Listing of composer birthdates |
| The Works of Ludwig van Beethoven | The dates of Beethoven's performances |
| George Frideric Handel | Performances of Handel's compositions |
| Gilbert and Sullivan Operas | Performances dates of G&S operas |
| Marcos J. Montes Date Archives | For date algorithms |
| Andrew's Summary of US Holidays | Formulas for common holidays |
| Musicals.net | For all the links for the Broadway Shows |
| Ultimate Band List | For all the links for the Chart Toppers |
| On Broadway WWW Info Page | Openings and closing of more Broadway Shows |